Method and System for Fast Synchronization and Data Reception for Frequency Hopping Wireless Communication Systems

ABSTRACT

Methods and systems for fast synchronization and data reception for frequency hopping wireless communication systems are disclosed. Aspects of one method may include receiving a plurality of RF signals corresponding to a plurality of hopping frequencies. The RF signals may be processed in parallel to determine a hopping sequence. For example, the plurality of RF signals may be down-converted to a corresponding plurality of IF or baseband signals. The down-converted signals may be combined together to a single combined signal, and the single combined signal may then be processed to determine the frequency hopping sequence.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

This application makes reference to, claims priority to, and claimsbenefit of U.S. Provisional Application Ser. No. 60/943,217 (AttorneyDocket No. 17961US01) filed Jun. 11, 2007. The above stated applicationis hereby incorporated herein by reference in its entirety.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[Not Applicable]

MICROFICHE/COPYRIGHT REFERENCE

[Not Applicable]

FIELD OF THE INVENTION

Certain embodiments of the invention relate to wireless communication.More specifically, certain embodiments of the invention relate to amethod and system for fast synchronization and data reception forfrequency hopping wireless communication systems.

BACKGROUND OF THE INVENTION

Some conventional systems support wireless communication betweenwireless devices. Such communication systems range from national and/orinternational cellular telephone systems to the Internet, and topoint-to-point in-home wireless networks. Each type of communicationsystem is designed, and hence operates, in accordance with relevantcommunication standards. For instance, wireless communication systemsmay operate in accordance with one or more standards including, but notlimited to, IEEE 802.11,Bluetooth, advanced mobile phone services(AMPS), digital AMPS, global system for mobile communications (GSM),code division multiple access (CDMA), local multi-point distributionsystems (LMDS), multi-channel-multi-point distribution systems (MMDS),and/or variations thereof.

Depending on the type of wireless communication system, a wirelesscommunication device, for example, a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, or home entertainment equipment, communicates directly orindirectly with other wireless communication devices. For directcommunications, also known as point-to-point communications, theparticipating wireless communication devices tune their receivers andtransmitters to the same channel, or channels, and communicate via thosechannel(s). Each channel may utilize one or more of the plurality ofradio frequency (RF) carriers of the wireless communication system. Forindirect wireless communication, each wireless communication devicecommunicates directly with an associated base station, for example, forcellular services, and/or an associated access point, for example, foran in-home or in-building wireless network, via an assigned channel orchannels.

In order for each wireless communication device to participate in awireless communication session, it may utilize a built-in radio, whichcomprises a receiver and/or a transmitter, and/or it may be coupled toan associated radio transceiver, for example, a station for in-homeand/or in-building wireless communication networks, or a RF modem. Thetransmitter converts data into RF signals by modulating the data inaccordance with the particular wireless communication standard. However,different communication systems may use different standards, forexample, the IEEE 802.11 standard and the Bluetooth standard, which mayshare the same RF spectrum.

In order to alleviate signal interference from various RF devicessharing an RF spectrum with other communication systems, a transmissionstandard may allow frequency hopping where information is transmitted atvarious frequencies at different time instances. In this manner, theenergy of the transmitted signal may be spread across the RF spectrumover the various channels allowed for communication. The advantage offrequency hopping may be that it spreads information across a wide bandof frequencies. Therefore, signals transmitted by other systems using aportion of the same frequency spectrum may appear to be noise to onlysome of the frequencies used in frequency hopping. Similarly, only aportion of frequency hopping transmission may interfere with signalstransmitted by other systems. Frequency hopping further providesresistance to multipath fading effects. Radio signals in some frequencybands are especially susceptible to multipath effects caused by theradio signal travelling over multiple paths with the reflections anddirect signal combining either constructively or destructively at thereceiver. With frequency hopping, data which is not successfullyreceived on some frequency hops may be retransmitted on anotherfrequency hop. In addition, with a technique called adaptive frequencyhopping, the radio system can use avoid hop frequencies which areexperiencing interference or multipath fading and utilize only those hopfrequencies at which communications are successfully being received. Adisadvantage of frequency hopping may be evident in cases where areceiving device may need to determine the frequency sequence used forfrequency hopping. The receiving device may need to serially scanvarious channels for a sufficient period of time in order to determinethe frequency hopping sequence. Since a receiver may have to acquiresynchronization prior to receiving data, the longer it takes to acquirethe synchronization, the period prior to which receiving of data mayoccur. For many applications, long periods prior to actual receiving ofdata may be intolerable.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

A system and/or method for fast synchronization and data reception forfrequency hopping wireless communication systems, substantially as shownin and/or described in connection with at least one of the figures, asset forth more completely in the claims.

Various advantages, aspects and novel features of the present invention,as well as details of an illustrated embodiment thereof, will be morefully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary wireless system, which may beutilized in connection with an embodiment of the invention.

FIG. 2 is a block diagram illustrating an exemplary RF receiver frontend, which may be utilized in connection with an embodiment of theinvention.

FIG. 3 is an exemplary graph illustrating frequency hopping, inconnection with an embodiment of the invention.

FIG. 4 is an exemplary block diagram illustrating a plurality of RFreceiver front ends, in accordance with an embodiment of the invention.

FIG. 5A is an exemplary block diagram illustrating a plurality of mixersin a RF receiver front end, in accordance with an embodiment of theinvention.

FIG. 5B is an exemplary block diagram illustrating a single mixer in aRF receiver front end, in accordance with an embodiment of theinvention.

FIG. 6 is an exemplary flow diagram for utilizing a plurality of RFreceiver front ends for fast synchronization and data reception, inaccordance with an embodiment of the invention.

FIG. 7 is an exemplary flow diagram for utilizing a plurality of mixersin a RF receiver front end for fast synchronization and data reception,in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Certain embodiments of the invention may be found in a method and systemfor fast synchronization and data reception for frequency hoppingwireless communication systems. Aspects of the method may comprisereceiving a plurality of RF signals corresponding to a plurality ofhopping frequencies. The plurality of RF signals may be processed inparallel to determine a hopping sequence. For example, the plurality ofRF signals may be down-converted to a corresponding plurality of IF orbaseband signals. The down-converted signals may be combined together togenerate a single combined signal. The single combined signal may thenbe processed to determine the frequency hopping sequence.

Another embodiment of the invention may generate in parallel a basebandsignal for each of the plurality of RF signals. These baseband signalsmay be processed to determine which baseband signal may compriseinformation needed to determine the frequency hopping sequence. Anotherembodiment of the invention may comprise generating a wideband signalthat encompasses information received via the plurality of RF signals.The wideband signal may then be processed to determine the frequencyhopping sequence.

FIG. 1 is a block diagram of an exemplary wireless system, which may beutilized in connection with an embodiment of the invention. Referring toFIG. 1, the wireless system 150 may comprise an antenna 151, atransmitter/receiver switch 151 a, a transmitter front end 152, areceiver front end 153, a baseband processor 154, a processor 156, and asystem memory 158. The transmitter/receiver switch 151 a may comprisesuitable circuitry that enables the antenna 151 to be used for bothreceiving and transmitting. The transmitter front end (TFE) 152 maycomprise suitable logic, circuitry, and/or code that may be adapted toup-convert a baseband signal directly to an RF signal and to transmitthe RF signal via a transmitting antenna 151. The TFE 152 may also beadapted to up-convert a baseband signal to an IF signal, and up-convertthe IF signal to a RF signal and then transmit the RF signal via thetransmitting antenna 151. The TFE 152 may be adapted to execute otherfunctions, for example, filtering the baseband signal, and/or amplifyingthe baseband signal.

The receiver front end (RFE) 153 may comprise suitable logic, circuitry,and/or code that may be adapted to down-convert a RF signal directly toa baseband signal for further processing. The RFE 153 may also beadapted to down-convert a RF signal to an IF signal, and down-convertthe IF signal to a baseband signal for further processing. The RFE 153may be adapted to execute other functions, for example, filtering thebaseband signal, and/or amplifying the baseband signal.

The baseband processor 154 may comprise suitable logic, circuitry,and/or code that may be adapted to process baseband signals, forexample, convert a digital signal to an analog signal, and/orvice-versa. The processor 156 may be a suitable processor or controllersuch as a CPU or DSP, or any type of integrated circuit processor. Theprocessor 156 may comprise suitable logic, circuitry, and/or code thatmay be adapted to control the operations of the TFE 152 and/or thebaseband processor 154. For example, the processor 156 may be utilizedto update and/or modify programmable parameters and/or values in aplurality of components, devices, and/or processing elements in the TFE152 and/or the baseband processor 154. Furthermore, if the wirelesssystem 150 comprises more than one processor, control and/or datainformation, which may include the programmable parameters, may betransferred from at least one controller and/or processor to theprocessor 156. Similarly, the processor 156 may be adapted to transfercontrol and/or data information, which may include the programmableparameters, to at least one controller and/or processor, which may bepart of the wireless system 150.

The processor 156 may utilize the received control and/or datainformation, which may comprise the programmable parameters, todetermine an operating mode of the TFE 152. For example, the processor156 may be utilized to select a specific frequency for a localoscillator, or a specific gain for a variable gain amplifier. Moreover,the specific frequency selected and/or parameters needed to calculatethe specific frequency, and/or the specific gain value and/or theparameters needed to calculate the specific gain, may be stored in thesystem memory 158 via the processor 156. The information stored insystem memory 158 may be transferred to the TFE 152 from the systemmemory 158 via the processor 156. The system memory 158 may comprisesuitable logic, circuitry, and/or code that may be adapted to store aplurality of control and/or data information, including parametersneeded to calculate frequencies and/or gain, and/or the frequency valueand/or gain value.

FIG. 2 is a block diagram illustrating an exemplary RF receiver frontend, which may be utilized in connection with an embodiment of theinvention. Referring to FIG. 2, there is shown amplifiers 210 and 218, amixer 212, an intermediate frequency local oscillator (IF LO) 214, abandpass filter 216, and a baseband generator 220. The amplifiers 210and 218 may comprise suitable logic, circuitry, and/or code that may beadapted to amplify input signals and output the amplified signals. Theamplifier 210 and/or the amplifier 218 may be a low noise amplifier(LNA). A LNA may be utilized in instances where the signal to noiseratio (SNR) may be relatively low, such as, for example, RF signalsreceived by an antenna. The amplifiers 210 and 218 may also be variablegain amplifiers, where the gain control may be, for example, under aprogrammable control of a processor/controller 156 (FIG. 1).

The mixer 212 may comprise suitable logic, circuitry, and/or code thatmay be adapted to receive two input signals, and generate an outputsignal, where the output signal may be a difference of the frequenciesof the two input signals or a sum of the frequencies of the two inputsignals.

The IF LO 214 may comprise suitable logic, circuitry, and/or code thatmay be adapted to output a signal of a specific frequency, either presetor variable under external control, where the external control may be avoltage. The latter type may be referred to as a voltage controlledoscillator (VCO). A VCO control voltage may be, for example, underprogrammable control of a processor/controller 156 (FIG. 1).

The bandpass filter 216 may comprise suitable logic, circuitry, and/orcode that may be adapted to selectively pass signals within a certainbandwidth while attenuating signals outside that bandwidth.

The baseband generator 220 may comprise suitable logic, circuitry,and/or code that may be adapted to generate analog baseband signal fromthe IF signal communicated by the amplifier 218. For example, analogdown-conversion of the IF signal to analog baseband signal may compriseusing a mixer (not shown) similar to the mixer 212. If the basebandprocessor 154 (FIG. 1) is a digital baseband processor, the analogbaseband signal may be converted to digital signal and communicated tothe baseband processor 154. An analog to digital converter (ADC) (notshown) may be utilized to digitize the analog IF signal.

Digital down-conversion may comprise digitizing the IF signal,processing the digitized IF signal, for example, filtering anddown-converting, to generate a digital baseband signal, which may thenbe communicated to the baseband processor 154. If the baseband processor154 (FIG. 1) is an analog baseband processor, the digital basebandsignal may be converted to analog baseband signal and communicated tothe baseband processor 154. A digital to analog converter (DAC) (notshown) may be utilized to convert the digital IF signal. Thedown-conversion of the digital IF signal to the digital baseband signalmay utilize, for example, decimation filters where the input frequencyof the decimation filter may be a multiple of the output frequency ofthe decimation filter. The digital filtering of the digital samples mayutilize a derotator that may utilize a coordinate rotation digitalcalculation (CORDIC) algorithm.

In operation, the RF signal, which may have a carrier frequency referredto as f_(RF), may be received by an antenna and communicated to theamplifier 210, where the RF signal may be amplified by the amplifier210. The amplified RF signal may be communicated to an input of themixer 212. The output signal of the LO 214, which may have a frequencyof f_(LO)=f_(RF)+f_(IF) or f_(LO)=f_(RF)−f_(IF), may be communicated toanother input of the mixer 212, where f_(IF) may be a desiredintermediate frequency. The mixer 212 may process the two input signalssuch that the output signal may have a desired frequency. The mixer 212output signal may be referred to as an IF signal.

The IF signal may be communicated to a bandpass filter 216, which may beadapted to pass the desired bandwidth of signals about the IF frequencyf_(IF), while attenuating the undesired frequencies in the IF signal.The filtered IF signal may be amplified by the amplifier 218, and theamplified IF signal may be communicated to the baseband generator 220.The baseband signal output by the baseband generator 220 may becommunicated to the baseband processor 154 for further processing. Theprocessing may comprise, for example, filtering and/or amplifying.

FIG. 3 is a graph illustrating frequency hopping, in connection with anembodiment of the invention. Referring to FIG. 3, there is shown a graphwith frequency on the vertical axis and time on the horizontal axis.There is also shown a range of frequencies from 2.402 gigahertz (GHz) to2.480 GHz. There is further shown a plurality of packets 300, 302, . . ., 322, transmitted at times t0, t1, . . . , t11. The frequency rangefrom 2.402 GHz to 2.480 GHz may be, for example, the spectrum utilizedby Bluetooth communication devices.

In operation, a device, which may be, for example, a Bluetooth device,may transmit packets where each packet may be transmitted at a differentfrequency. This may be referred to as frequency hopping. One advantageof frequency hopping may be that the information transmitted may bespread over a wide spectrum of frequencies, and, therefore, noise at anypart of the spectrum may only affect a portion of the informationtransmitted. The noise may be any signal in the transmit frequency rangethat affects the transmitted information.

As an illustration, Bluetooth devices within a piconet use a commonhopping sequence that is a function of the Bluetooth clock of the masterBluetooth device in the piconet. However, if a slave Bluetooth devicehas not communicated with the master Bluetooth device for a period oftime, or if the slave Bluetooth device is new to the piconet, the slaveBluetooth device may need to synchronize to the clock of the masterBluetooth device. The synchronization occurs when the slave Bluetoothdevice receives an FHS (Frequency Hopping Synchronization) packettransmitted by the master Bluetooth device.

The master Bluetooth device may have acquired the slave Bluetoothdevice's address during inquiry phase. The clock offset synchronizationhop frequencies used to achieve a connection with a slave Bluetoothdevice are a function of the device address of the slave device.Accordingly, a slave device that wishes to communicate with a masterdevice may listen to a set of paging hop frequencies that is a functionof the slave's device address. Once the slave device synchronizes withthe master device clock, the slave device may be able to receive packetsat the various hop frequencies used by the master device.

FIG. 4 is an exemplary block diagram illustrating a plurality of RFreceiver front ends, in accordance with an embodiment of the invention.Referring to FIG. 4, there is shown a plurality of RFEs 410, 412, . . ., 414, a plurality of ADCs 410 a, 412 a, . . . , 414 a, and a basebandprocessor 420. The RFEs 410, 412, . . . , 414 may each be similar to theRFE 153, and the baseband processor 420 may be similar to the basebandprocessor 154.

In operation, the RFEs 410, 412, . . . 414 may be used to receivesignals at specific hop frequencies. The number of hop frequencies thatmay be monitored may depend on the number of RFEs, which may be designdependent. Accordingly, when a receiving device needs to synchronize tothe current hopping sequence, the plurality of RFEs 410, 412, . . . ,414 may be used to simultaneously receive signals at various hopfrequencies. The received baseband signals may be communicated to thebaseband processor 420 for further processing. A processor, such as, forexample, the baseband processor 420 and/or the processor 156, mayidentify whether any of the baseband signals may comprise appropriateinformation, such as a device address, from the transmitting device.

For example, if the transmitting device is a master Bluetooth device,the baseband processor 420 and/or the processor 156 in the slaveBluetooth device may monitor baseband signals from the various paginghop frequencies. Once the slave Bluetooth device receives its deviceaccess code via a baseband signal from one of the RFEs 410, 412, . . . ,414, the slave Bluetooth device may proceed to connect with the masterBluetooth device. If the number of RFEs 410, 412, . . . , 414 is lessthan the number of paging hop frequencies used, for example, forBluetooth paging, the frequencies that the RFEs 410, 412, . . . , 414are monitoring may be changed after an appropriate time period haselapsed. For example, the appropriate time period may be a time periodbetween successive transmissions of a slave Bluetooth device's accesscode. Accordingly, an amount of time needed to synchronize to the masterBluetooth clock may be reduced by using the plurality of RFEs 410, 412,. . . , 414 rather than a single RFE, where the single RFE may need toserially monitor a different frequency after each scan window period.

Additionally, a non-Bluetooth wireless standard may allow a receivingdevice to determine the hopping sequence based on tracking the hoppingfrequencies used by a presently transmitting device. The receivingdevice may then use the hopping sequence to receive packets and/ortransmit packets by tuning the RF circuitry to appropriate frequencies.Accordingly, the plurality of RFEs 410, 412, . . . , 414 may be used toquickly determine the frequencies being used since the RFEs 410, 412, .. . , 414 may be used to monitor the various hopping frequencies thatmay be used by the transmitting device.

FIG. 5A is an exemplary block diagram illustrating a plurality of mixersin a RF receiver front end, in accordance with an embodiment of theinvention. Referring to FIG. 5A, there is shown a RFE 500 that maycomprise a plurality of mixers 502, 504, . . . , 506, and a plurality oflocal oscillators (LOs) 502 a, 504 a, . . . , 506 a. The mixers 502,504, . . . , 506 may each be similar to the mixer 212, and the LOs 502a, 504 a, . . . , 506 a may each be similar to the LO 214.

In operation, the mixers 502, 504, . . . , 506 may be used todown-convert received RF signals to IF signals. For example, each of themixers 502, 504, . . . , 506 may receive a different signal from the LOs502 a, 504 a, . . . , 506 a, respectively, to down-convert a RF signalat a specific frequency to an IF signal. The IF signals from the mixers502, 504, . . . , 506 may be combined to form a single IF signal, whichmay then be processed to a baseband signal by the RFE 500. The number ofRF frequencies that may be down-converted may depend on the number ofmixers 502, 504, . . . , 506, which may be design dependent.

Accordingly, if, for example, the Bluetooth communication standard isused for explanatory purposes, when a slave Bluetooth device, needs tosynchronize to the master Bluetooth device, the RFE 500 may be used tosimultaneously down-convert a plurality of paging hop frequency signalsto a single baseband signal. The single baseband signal may then becommunicated to, for example, the baseband processor 154 for furtherprocessing. A processor, such as, for example, the baseband processor154 and/or the processor 156 may then determine whether the basebandsignal may comprise appropriate information, such as, for example, anaccess code, from the master Bluetooth device.

The baseband processor 154 and/or the processor 156 in the slaveBluetooth device may monitor the combined baseband signal from thevarious paging hop frequencies. Once the slave Bluetooth device receivesits access code via the baseband signal, the slave Bluetooth device mayproceed to make a channel connection with the master Bluetooth device.However, this may require identifying the specific paging hop frequencythat was used to transmit the device address. In order to determinewhich paging hop frequency was used to transmit the device address, themaster Bluetooth device may need to transmit a channel number with thedevice address, where a specific channel number may correspond to aspecific hop frequency. Alternatively, the master Bluetooth device maytransmit clock information which enables the slave Bluetooth device tocalculate the offset of its own clock relative to the master's clock.The slave Bluetooth device may then be able to determine the paging hopfrequency used, and, therefore, be able to communicate with the masterBluetooth device.

If the number of mixers is less than the number of paging hopfrequencies used, for example, for Bluetooth paging, the frequenciesthat the mixers are down-converting may be changed after an appropriatetime period has elapsed. For example, the appropriate time period may bea time period for successive transmission of a slave Bluetooth device'saccess code by the Bluetooth master device. Accordingly, the time neededto synchronize to the master Bluetooth clock may be reduced by using theplurality of mixers in a RFE rather than a single mixer in a RFE, wherethe single mixer may be used to serially monitor a different frequencyduring each scan window period.

Additionally, a non-Bluetooth wireless standard may allow a receivingdevice to determine the hopping sequence based on tracking the hoppingfrequencies used by a presently transmitting device. The receivingdevice may then use the hopping sequence to receive packets and/ortransmit packets by tuning the RF circuitry to appropriate frequencies.Accordingly, the plurality of mixers 502, 504, . . . , 506 may be usedto quickly determine-the frequencies being used since the mixers 502,504, . . . , 506 may be used to monitor the various hopping frequenciesthat may be used by the transmitting device.

FIG. 5B is an exemplary block diagram illustrating a single mixer in aRF receiver front end, in accordance with an embodiment of theinvention. Referring to FIG. 5B, there is shown a RFE 510 that maycomprise a mixer 512 and a continuous wave local oscillator (CW LO) 512a. The mixer 512 may be similar to the mixer 212. The CW LO 512 a maycomprise circuitry and/or logic that may enable generation of several CWtones 514. Spectrally, the output of the CW LO 512 a may be described asa “comb,” where each tooth of the comb may be a specific frequency.

In operation, the mixer 512 may be used to down-convert received RFsignals to IF signals. For example, the mixer 512 may receive a signalfrom the CW LO 512 a to down-convert each of the received RF signals toan IF signal with a same frequency. Accordingly, the received RF signalsmay be down-converted and combined to form a single IF signal, which maythen be processed to a baseband signal by the RFE 500. The number of RFfrequencies that may be down-converted may depend on the number ofcontinuous wave tones from the CW LO 512, which may be design dependent.Furthermore, each of the CW tones 514 in the “comb” may be selectivelyturned on or off. Turning each of the CW tones 514 on or off may becontrolled by a processor, such as, for example, the baseband processor154 and/or the processor 156. A CW tone that may correspond to a pagingfrequency where there may be significant interference may be selectivelyand dynamically turned off, allowing the system to adapt to noisyenvironments. One or more of the CW tones 514 may also be turned off ifthe system knows in advance that some of those frequencies used by thoseCW tones may also be used by another RF system operating in closeproximity.

Accordingly, if, for example, the Bluetooth communication standard isused for explanatory purposes, when a slave Bluetooth device, needs tosynchronize to the master Bluetooth device, the RFE 500 may be used tosimultaneously down-convert a plurality of paging hop frequency signalsto an IF signal or directly to a single baseband signal. The singlebaseband signal may then be communicated to, for example, the basebandprocessor 154 for further processing. A processor, such as, for example,the baseband processor 154 and/or the processor 156 may then determinewhether the baseband signal may comprise appropriate information, suchas, for example, an access code, from the master Bluetooth device.

The baseband processor 154 and/or the processor 156 in the slaveBluetooth device may monitor the combined baseband signal from thevarious paging hop frequencies. Once the slave Bluetooth device receivesits access code via the baseband signal, the slave Bluetooth device mayproceed to make a channel connection with the master Bluetooth device.However, this may require identifying the specific paging hop frequencythat was used to transmit the device address. In order to determinewhich paging hop frequency was used to transmit the device address, themaster Bluetooth device may need to transmit a channel number with thedevice address, where a specific channel number may correspond to aspecific hop frequency. Alternatively, the master Bluetooth device maytransmit clock information which enables the slave Bluetooth device tocalculate the offset of its own clock relative to the master's clock.The slave Bluetooth device may then be able to determine the paging hopfrequency used, and, therefore, be able to communicate with the masterBluetooth device.

If the number of CW tones from the CW LO 512 is less than the number ofpaging hop frequencies used, for example, for Bluetooth paging, the RFfrequencies that are down-converted may be changed after an appropriatetime period has elapsed. For example, the appropriate time period may bea time period for successive transmission of a slave Bluetooth device'saccess code by the Bluetooth master device. Accordingly, the time neededto synchronize to the master Bluetooth clock may be reduced by using theCW LO 512 a in a RFE rather than a single LO and a single mixer in aRFE.

Additionally, a non-Bluetooth wireless standard may allow a receivingdevice to determine the hopping sequence based on tracking the hoppingfrequencies used by a presently transmitting device. The receivingdevice may then use the hopping sequence to receive packets and/ortransmit packets by tuning the RF circuitry to appropriate frequencies.Accordingly, the CW LO 512 a and the mixer 512 may be used to quicklydetermine the frequencies being used since the various LO frequenciesfrom the CW LO 512 a may be used to monitor the various hoppingfrequencies that may be used by the transmitting device.

FIG. 6 is an exemplary flow diagram for utilizing a plurality of RFreceiver front ends for fast synchronization and data reception, inaccordance with an embodiment of the invention. Referring to FIG. 6,there is shown steps 600 to 610 for determining a hopping sequence. Instep 600, the wireless system 150 may be configured so that the RFEs410, 412, . . . , 414 may each de-modulate a hopping frequency signal toa baseband signal. Each of the baseband signals may be processed by, forexample, the baseband processor 154 and/or the processor 156 todetermine a hopping sequence to be used for communication between/amongwireless systems. In step 602, a scan window may be started. The scanwindow may be a period of time during which a receiving device mayattempt to determine a hopping sequence.

In step 604, the RFEs 410, 412, . . . , 414 may monitor a plurality ofdifferent hopping frequencies to determine a hopping sequence. Forexample, a wireless standard may enable determining of a hoppingsequence by tracking a pre-determined number of hopping channels.Accordingly, the RFEs 410, 412, . . . , 414 may be used to track thevarious hopping frequencies used. The wireless system 150 may then beable to determine a hopping sequence for communication with thepresently transmitting device, which may be similar, for example, to thewireless system 150.

In step 606, if the wireless system 150 received enough information tobe able to determine a hopping sequence, the next step is step 608.Otherwise, the next step is step 610. In step 608, the hopping sequencemay be used by the wireless system 150 for communicating with thepresently transmitting device. In step 610, if the scan window period isnot yet over, the next step is step 604. Otherwise, the next step isstep 600.

FIG. 7 is an exemplary flow diagram for utilizing a plurality of mixersin a RF receiver front end for fast synchronization and data reception,in accordance with an embodiment of the invention. Referring to FIG. 7,there is shown steps 700 to 714 for determining a hopping sequence. Instep 700, the wireless system 150 may be configured so that the mixers502, 504, . . . , 506 may each de-modulate a hopping frequency signal toan IF signal. In step 702, a scan window may be started. The scan windowmay be a period of time during which a receiving device may attempt todetermine a hopping sequence. In step 704, each of the mixers 502, 504,. . . , 506 may down-convert a corresponding hopping frequency signal toan IF signal. In step 706, the IF signals from the outputs of the mixers502, 504, . . . , 506 may be combined, and then the combined IF signalmay be further down-converted to a baseband signal. The baseband signalmay be communicated to, for example, the baseband processor 154 forfurther processing.

In step 708, the baseband processor 154 and/or the processor 156 maymonitor the baseband signal to determine a hopping sequence. Forexample, a wireless standard may enable determining of a hoppingsequence by tracking a pre-determined number of hopping channels.Accordingly, the mixers 502, 504, . . . , 506 may be used to track thevarious hopping frequencies used since one hopping frequency may be usedat a time. However, the transmitting device may need to transmit ahopping channel, which may correspond to a hopping frequency, with thedata transmitted. In this manner, the receiving device may be able todetermine the hopping frequency used for each transmission. The wirelesssystem 150 may then be able to determine a hopping sequence forcommunication with the presently transmitting device, which may besimilar, for example, to the wireless system 150.

In step 710, if the wireless system 150 received enough information tobe able to determine a hopping sequence, the next step is step 712.Otherwise, the next step is step 714. In step 710, the hopping sequencemay be used by the wireless system 150 for communicating with thepresently transmitting device. In step 714, if the scan window period isnot yet over, the next step is step 704. Otherwise, the next step may is700.

Another embodiment of the invention may comprise wideband processing ofthe received RF signals. For example, the RFE 153 may comprise suitablecircuitry, logic, and/or code that may be enabled to down-convert thereceived RF signal to a wideband signal where the wideband signal maycomprise the information transmitted via the various hoppingfrequencies. The wideband signal may then be digitally sampled, and thedigital samples may be communicated to the baseband processor 154 forfurther processing. The baseband processor 154 and/or the processor 156may process the digital samples to determine whether, for example, adevice address may have been received. The baseband processor 154 and/orthe processor 156 may be able to determine a hopping frequency that mayhave been used to transmit the device address, for example, bydetermining the frequency offset at which the information was found.

In accordance with an embodiment of the invention, aspects of anexemplary system may comprise at least one receiver front end (RFE) thatenables reception of plurality of RF signals corresponding to aplurality of hopping frequencies. A processor, such as, for example, thebaseband processor 154 and/or the processor 156, may be used to processthe received signals for information that may be used to determine ahopping sequence. For example, when wireless devices are using theBluetooth standard, a master Bluetooth device may transmit a slaveBluetooth device's access code. The slave Bluetooth device may determinethat the-transmitted access code is its own access code, and hence maybe able to identify the hopping sequence used by the master Bluetoothdevice.

Similarly, another wireless standard may allow determination offrequency hopping sequences by identifying a certain number of thefrequencies used for transmission. If a hopping frequency is only usedonce in a frequency hopping sequence, then transmission of data ortraining sequence may only need to be identified for one hoppingfrequency. Accordingly, the receiving device may then be able todetermine the next hopping frequency to use for communicating with otherwireless devices.

A plurality of RFEs 410, 412, . . . , 414 may be used to generate abaseband signal from the signals received by each of the front endcircuitry. Each of the RFEs 410, 412, . . . , 414 may process inparallel the signals received via one of the plurality of hoppingfrequencies. The baseband signals from the plurality of RFEs 410, 412, .. . , 414 may be communicated to, for example, the baseband processor420 for further processing. The baseband processor 420 and/or theprocessor 156 may process the baseband signal for the information neededto determine the frequency hopping sequence.

Another embodiment of the invention may comprise a RFE, such as, forexample, the RFE 153 that may enable generation of a wideband signalcomprising information received via the plurality of RF signals. Thewideband signal may be processed, and a specific hopping frequency viawhich the information was received may be identified by calculating thefrequency offset of the channel from which the information was received.A channel may be a hopping frequency.

Another embodiment of the invention may comprise a plurality of mixers502, 504, . . . , 506 that may be used to down-convert each of thereceived RF signals. The down-converted signals may be IF signals or thedown-converted signals may be baseband signals. The down-convertedsignals may be combined with each other to form a single signal. If thedown-converted signal is an IF signal, the combined single signal may befurther down-converted to a baseband signal. If the outputs of themixers 502, 504, . . . , 506 are currents, then the outputs of themixers 502, 504, . . . , 506 may be directly coupled to each other tocombine the currents. The single combined signal may be communicated tothe baseband processor 154 for further processing. The basebandprocessor 154 and/or the processor 156 may be used to extract requiredinformation from the single combined signal. However, because the singlecombined signal may not have the hopping frequency information, atransmitting device may need to transmit hopping frequency informationalong with data, such as a device address, training sequence, or otherpayload.

Another embodiment of the invention may comprise the CW LO 512 a and asingle mixer 512 for simultaneously down-converting each of a pluralityof received RF signals. The CW LO 512 a may generate, for example, aplurality of continuous wave tones. The CW LO 512 a may also becontrolled to turn off one or more CW tones, for example, if aparticular RF frequency associated with a CW tone is very noisy, or ifanother RF device is using an RF frequency associated with that CW tone.

Another embodiment of the invention may provide a machine-readablestorage, having stored thereon, a computer program having at least onecode section executable by a machine, thereby causing the machine toperform the steps as described above for fast synchronization and datareception for frequency hopping wireless communication systems.

Accordingly, the present invention may be realized in hardware,software, or a combination of hardware and software. The presentinvention may be realized in a centralized fashion in at least onecomputer system, or in a distributed fashion where different elementsare spread across several interconnected computer systems. Any kind ofcomputer system or other apparatus adapted for carrying out the methodsdescribed herein is suited. A typical combination of hardware andsoftware may be a general-purpose computer system with a computerprogram that, when being loaded and executed, controls the computersystem such that it carries out the methods described herein.

The present invention may also be embedded in a computer programproduct, which comprises all the features enabling the implementation ofthe methods described herein, and which when loaded in a computer systemis able to carry out these methods. Computer program in the presentcontext means any expression, in any language, code or notation, of aset of instructions intended to cause a system having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: a) conversion to anotherlanguage, code or notation; b) reproduction in a different materialform.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willcomprise all embodiments falling within the scope of the appendedclaims.

1. A method for wireless communication, the method comprising: receivinga plurality of RF signals corresponding to a plurality of hoppingfrequencies; and processing said plurality of received RF signals inparallel to determine a hopping sequence.
 2. The method according toclaim 1, comprising generating in parallel baseband signals thatcorrespond to each of said plurality of received RF signals.
 3. Themethod according to claim 2, comprising determining said hoppingsequence from said generated baseband signals.
 4. The method accordingto claim 1, comprising generating a wideband signal that encompassesinformation received via said plurality of received RF signals.
 5. Themethod according to claim 4, comprising determining said hoppingsequence from said generated wideband signal.
 6. The method according toclaim 1, comprising generating a down-converted signal for each of saidplurality of received RF signals.
 7. The method according to claim 6,wherein said down-converted signal is an IF signal.
 8. The methodaccording to claim 6, wherein said down-converted signal is a basebandsignal.
 9. The method according to claim 6, comprising combining saiddown-converted signals to a single combined signal.
 10. The methodaccording to claim 9, comprising determining said hopping sequence fromsaid single combined signal.
 11. A system for wireless communication,the system comprising: one or more circuits that receive a plurality ofRF signals corresponding to a plurality of hopping frequencies; said oneor more circuits process said plurality of received RF signals inparallel to determine a hopping sequence.
 12. The system according toclaim 11, wherein said one or more circuits comprise a plurality ofreceiver front end circuits that enable generation in parallel ofbaseband signals where each of said baseband signals corresponds to eachof said plurality of received RF signals.
 13. The system according toclaim 12, wherein said baseband signals are further processed todetermine said hopping sequence.
 14. The system according to claim 11,wherein said one or more circuits comprise a receiver front end circuitthat enables generation of a wideband signal that encompassesinformation received via said plurality of received RF signals.
 15. Thesystem according to claim 14, wherein said wideband signal is furtherprocessed to determine said hopping sequence.
 16. The system accordingto claim 11, wherein said one or more circuits comprise a receiver frontend circuit comprising a plurality of mixers that enable generation of adown-converted signal for each of said plurality of received RF signals.17. The system according to claim 16, wherein said down-convertedsignals is an IF signal.
 18. The system according to claim 16, whereinsaid down-converted signals is a baseband signal.
 19. The systemaccording to claim 16, comprising a combining circuit that enablescombining of said down-converted signals to a single combined signal.20. The system according to claim 19, wherein said single combinedsignal is further processed to determine said hopping sequence.
 21. Thesystem according to claim 11, wherein said one or more circuits comprisea receiver front end circuit comprising a single mixer using one or morecontinuous wave signals from a continuous wave local oscillator, whereinsaid single mixer enables generation of a down-converted signal for eachof said plurality of received RF signals.
 22. The system according toclaim 21, wherein said one or more circuits enable generation of each ofsaid one or more continuous wave signals.